Friday, November 11th, 2011...3:44 pm

Visualizing the numbers

Did you know that math helped pick your clothes today? Indeed, you dressed up with math! One particular way this is true relates to the clothes you buy in a store. Your choices are constrained by the selections in the store.

Graphs and charts are useful ways of representing many forms of data. A variety of different types of graphs appear frequently in the news.

First, we’ll go to the bar. Bar charts are a very popular and common means of visualizing data. We’ve all seen a bar chart with one bar telling us the progress of a computing device.

Picture credit: http://i.msdn.microsoft.com/dynimg/IC46037.png

Bar charts that use multiple bars enable us to quickly sense the relative size of different quantities. For instance, consider this chart depicting celebrity earnings from 2010 taken from Hollywood’s Highest Paid Stars 2011. (Click the image if you’d like to see it larger.)

Looking at the chart above, about how much more did Johnny Depp make last year than Nicolas Cage? Even without knowing the exact amounts, you can look at the relative sizes of the bars to get a sense.

Got pie?

A pie chart subdivides a circle into “slices” where each sector corresponds to a category. The area of each sector is proportional to the percentage of the items in that category. Keep in mind that a chart is intended to give useful information in a visual way. Let’s see some charts that aren’t as successful at displaying helpful information.

While bar and pie charts are rather standard ways to visualize data, keep in mind that many other techniques are being used and developed. For example, here is a visualization of 30 school district mission/vision statements. This is very similar to the word cloud that appears in this blog that represents the frequency of different tags I use for my blog posts.